Frederick Jones, Jr., or Fred for short, is the leader of the Mystery Incorporated gang and a founding member of it. He enjoys creating traps to the point that he was obsessed with it (his obsession has been toned down a little, although he is still an enthusiast and expert in the subject, much to his father's annoyance). Of the five members, he is the most physically fit, and usually uses that to his advantage when he needs to overpower someone. Fred has been a bit clueless about other people's feelings, especially in regard to Daphne, although he seems to be getting better in that field.
Frank Welker is the only actor that has voiced the same character since 1969's Scooby-Doo Where Are You? (except for in A Pup Named Scooby-Doo)
Casey Kasem (Shaggy) retired his voice lending for Shaggy, although he did voice Shaggy's father; Don Messick (Scooby) died in 1997, but had retired from doing Scooby in 1995; Daphne had two voice actresses (Stefanianna Christopherson & Heather North), both of whom retired; Velma also had two voice actresses (Nicole Jaffe & Pat Stevens), both of whom retired (Stevens died in 2010).
The Mystery Incorporated version of Fred who appears in FusionFall is vastly different from his earlier incarnations, though his appearance is based on his 60's version.